KR100361041B1 - Hybrid power train vehicle and its control method - Google Patents

Abstract

The output speed of the engine 1 is controlled to achieve optimum efficiency by adjusting the input speed of the continuously variable transmission CVT: 3. If an output above the output generated by the engine 1 is required, additional power is input from the pump motor 7 driven by the fluid pressure stored in the accumulator 6 into the drive train. In a running state in which the engine 1 operating at optimum efficiency generates an output above the power required by the vehicle, the pump motor 7 is converted to operate as a pump, and the excessive engine output is used to drive the pump and the shaft Energy is stored in the form of fluid pressure in the inflator 6. The microprocessor determines the required output of the engine as the sum of the outputs presented by the sensors 14, which outputs the output required by the driver and the output increment required to maintain the pressure of the accumulator 6 above a threshold. Detect.

Description

Hybrid powertrain vehicle and control method thereof

As vehicle use increases, many sources of pollution, including greenhouse gases such as carbon dioxide, increase in the atmosphere. For these reasons, efforts have been made to improve the utilization of fuel for vehicle powertrains. Typically, current powertrains have thermal efficiency of only about 10% to 15%.

Prior art vehicle powertrains generate significant energy losses, making it difficult to control emissions effectively and offer limited possibilities for seeking significant improvements in vehicle fuel savings. The powertrain of the prior art consists of an internal combustion engine, a simple mechanical transmission with a distinct gear ratio stage. Due to the inefficiency, about 80% to 90% of the fuel energy consumed by the system is disposed of as heat. Only 10% to 15% of the energy is used to propel the vehicle, and a significant amount of energy is dissipated as heat during braking.

Significant energy losses are due to an inadequate combination between engine power capacity and average power demand. The load on the engine at a given moment is directly determined by the total road load at that moment, and the overall road load varies between extremely high loads and extremely small loads. In order to meet the acceleration demand, the engine must generate power that is several times the average power to propel the vehicle. The efficiency of the internal combustion engine varies considerably from road to road, highest at high loads close to the highest load, and lowest at low loads. Since normal engine operation is almost always at the bottom of the load range, even with the highest efficiency in the range of 35% to 40% of some prior art engines, the engine's efficiency is poor for most of the time.

Another major source of energy loss is related to braking. In contrast to the acceleration, which must transfer the energy of the wheels, the braking action must remove energy from the wheels. Since internal combustion engines only generate energy and do not reproduce, prior art powertrains have a one-way energy path. Braking is achieved by a friction braking system, which temporarily converts unnecessary kinetic energy into heat, making the kinetic energy of the vehicle useless.

Due to the wide range of loads and speeds imposed on the engine in prior art powertrains, it is difficult to control emissions efficiently because the engine must operate in a number of different combustion conditions. By operating the engine at a more constant speed and load, the emissions control can be optimized much better, and overall fuel consumption per travel can be reduced by more efficient engine setting.

Prior art powertrains limit the possibility of improving vehicle fuel savings, except when improvements in aerodynamic drag weights and rolling resistance are provided. This improvement merely provides a limited improvement in efficiency and can be applied well with the improved powertrain.

Hybrid vehicle systems have been studied as a means to reduce the inefficiency. In order to mitigate the change in the power demand imposed on the engine, the hybrid vehicle system provides a "buffer" between the power generated by the internal combustion engine and the power for propulsion of the vehicle. Because the buffer can receive and store energy from sources other than the engine, regenerative braking is allowed by the buffer. The efficiency of a hybrid vehicle system depends on the capacity of the engine to operate at peak efficiency and the capacity and efficiency of the buffer medium. Typical buffer media include electric batteries, mechanical flywheels and hydraulic accumulators.

In order to use a hydraulic accumulator as a buffer, a hydraulic pump / motor is integrated in the system. The pump / motor interacts as a pump or a motor. The pump / motor uses an engine or “braking” output to pressurize the hydraulic fluid to the accumulator as a pump, and the hydraulic fluid is compressed against a certain amount of gas (eg nitrogen). Fluid compressed as a motor is discharged through the pump / motor to generate power.

Hydraulic hybrid vehicle systems take two general forms. According to the "serial structure" system, all the energy generated by the engine is transmitted through the hydraulic output path, and the fluid output side exerts a variable road load. Thus, the efficiency of the fluid output path is not sensitive to changes in power demand and the engine is independent of road load, which increases the efficiency since the engine can run or stop at peak efficiency.

In-line systems are relatively simple in control and concept, but are less efficient than other systems because all energy must be converted to fluid output and restored to mechanical output to propel the vehicle. For optimum efficiency the tandem systems rely on frequent starting or stopping of the engine. The "parallel structure" system separates output flow between the direct and prior art mechanical drive lines and fluid power lines. Thus, part of the energy is converted to fluid power and stored. The most common form of the system is in the "start-up" mode, in which the primary energy is used to store the braking energy and to assist the next vehicle acceleration. Since the parallel system requires the prior art and hydraulic power path for the wheels, it tends to be more complicated and smoother than the tandem system. Depending on the particular design, the engine size can be reduced somewhat by the tandem and parallel systems, but relatively large engines are still required.

For example, according to US Patent No. 4,223,532 (September 23, 1980) issued to Mr. Seaber, a hydraulic hybrid transmission system based on the theory of using two pumps / motors to form intermittent engine operation. Is released.

The present invention relates to the design of a hybrid powertrain for a vehicle that can utilize the energy generated by an integrated internal combustion engine or an external combustion engine very efficiently. The present invention is applied to a propulsion system for a vehicle.

1 is a schematic diagram showing a first embodiment of a vehicle having a hybrid powertrain propulsion system according to the present invention;

2A, 2B, 2C and 2D are graphs showing engine load versus engine speed in the various modes of operation of the system shown in FIG.

3 is a schematic representation of a vehicle with a second embodiment of a hybrid propulsion system in accordance with the present invention.

4 is a schematic representation of a vehicle with a third embodiment of a hybrid powertrain propulsion system in accordance with the present invention.

5 is a schematic representation of a vehicle with a fourth embodiment of a hybrid powertrain propulsion system in accordance with the present invention.

6 is a logic flow diagram for controlling vehicle operation by a microprocessor in accordance with the present invention.

* Symbol description *

1, 10 ... engine 2, 9 ... drive shaft

3 ... Transmission 4 ... Freewheel Clutch

5 ... wheel 6 ... accumulator

7 ... pump / motor 11 ... clutch

12 ... vehicle speed sensor 42,44,46 ... processor

It is therefore an object of the present invention to provide a hybrid powertrain vehicle that can significantly reduce the size of an internal combustion engine of a vehicle.

It is a further object of the present invention to provide a powertrain system in which the internal combustion engine of a vehicle can be operated constantly at near maximum efficiency.

It is still another object of the present invention to (1) generate insufficient driving torque for an internal combustion engine, and (2) generate a driving force when the output demand is very small when the engine operation is inefficient, such as a stabilization body. It is to provide a hybrid propulsion system which is formed by an internal combustion engine and in which currently unnecessary power can be stored in a "buffer".

It is a further object of the present invention to provide a power train design in which energy generated by an internal combustion engine can be used more efficiently than in the prior art.

It is a further object of the present invention to provide a hybrid powertrain propulsion system that allows for significant changes in road load while maintaining high efficiency.

According to the present invention, there is provided an operating method and a "parallel" hybrid propulsion system that meet the above objects. Specifically, the hybrid powertrain of the present invention includes a vehicle frame supported on a road surface by driving wheels rotatably mounted on the vehicle frame. A first engine, such as an internal combustion engine or an external combustion engine, mounted on a vehicle frame, provides engine power through an output shaft according to the prior art. An output storage device is also mounted on the vehicle frame to store or release the braking output or the "over" engine output, so as to act as a "buffer". The first drivetrain transmits engine power to the drive wheels and includes a CVT (or multiple gear ratio transmission) including pulleys that are movable with variable effective diameter.

In a preferred embodiment, it is driven by the accumulator fluid pressure in the first mode, by the first drive train to transmit the motor output to the first drive train and to store the fluid pressure in the accumulator in the second mode. To act as a driven pump, a reversible fluid displacement means or "reversible pump / motor" is arranged between the accumulator of the fluid pressure and the first drive train. In still other embodiments, for example, the power storage device may be composed of a combination of a storage battery, a generator / alternator and an electric motor.

The second drive train connects the power storage device to the first drive train and forms a "parallel structure" propulsion system.

The control action of the propulsion system is partly based on three sensors: a vehicle speed sensor, for example a power storage sensor such as a pressure sensor for sensing fluid pressure inside the pressure gauge and for example a "throttle" pedal position or " It is formed by a torque (or power) demand sensor for sensing the torque (or power) required by the driver for the vehicle, such as a sensor for detecting the pressure of the "pedal" pedal. Comparing means for comparing the sensed value of the stored power with the determined minimum value of the stored power and generating a request signal when it is determined that the detected value is less than or equal to the determined minimum value of the stored power is included in the microprocessor. Torque output determining means for determining the additional torque in accordance with the request signal and determining the engine output torque as the sum of the detected torque demand value and the additional torque is included in the microprocessor. The microprocessor includes an engine speed determination processor for determining an engine speed of optimum efficiency according to the determined engine output torque and the detected vehicle speed, and outputting a shift signal representing the determined engine speed. By changing the gear ratio of the transmission, the engine speed control means controls the rotation speed of the engine output shaft. In a preferred embodiment, to control the rotational speed of the engine output shaft, the effective diameter of the pulley configured in the continuously variable transmission is changed in response to the shift signal output of the engine speed determination processor. The engine load controller controls the engine output by controlling the fuel supply to the first engine in response to the shift signal. The mode controller operates to switch the output storage device between the power storage mode and the power discharging mode. In a preferred embodiment, the mode controller, in response to the request signal, switches the operation of the fluid displacement means between the first mode and the second mode, and the displacement of the fluid displacement means in response to the sensed fluid pressure. Changed by the mode controller.

Optionally, a second engine, such as an internal combustion engine, is mounted on the vehicle frame to provide additional engine capacity, for example necessary to climb a steep slope. When the second engine is mounted on the vehicle, a second engine clutch is arranged between the output of the first drive train and the second engine to match the output speed of the second engine with the output of the first engine.

Optionally, the propulsion system of the present invention has a freewheel clutch for separating the wheels from the first drive train between the drive wheels and the transmission CVT in response to a signal indicating that the output demand is zero.

In the present invention, the propulsion system is controlled by sensing the vehicle speed, sensing the fluid pressure inside the accumulator to sense the output required by the driver for the vehicle. In response to fluid pressure and torque demands stored inside the accumulator, a reversible fluid displacement device (pump / motor) is switched between pump mode and motor mode. If the sensed fluid pressure is compared with the determined minimum fluid pressure and it is determined that the sensed fluid pressure is less than the minimum fluid pressure, a request signal is generated. The additional torque required to properly raise the fluid pressure is determined in accordance with the request signal, and the engine output torque is determined as the sum of the detected torque demand and the determined additional torque. The rotational speed of the output shaft is controlled by the engine speed controller by changing the effective pulley diameter of the CVT in response to the shift signal. The engine speed of optimum efficiency in accordance with the determined engine output torque and the detected vehicle speed is determined by the engine speed processor, and a shift signal indicative of the determined engine speed is output by the engine speed processor. The engine output is controlled by controlling the fuel supply to the engine in response to the shift signal.

In contrast to the prior art, the present invention requires a very small first engine and uses a hydraulic auxiliary system to keep the engine as much as possible, and only one pump / motor in the first drivetrain is required.

The present invention relates to a "parallel" system, but can be operated in series. The system of the present invention includes a very small engine of a size corresponding to an average power requirement rather than a peak power requirement. The hydraulic auxiliary system acts as a power reducer to "reduce" the power demands on the engine. That is, the purpose of the hydraulic auxiliary system is to apply an additional load to the engine when the propulsion output demand is small and to transmit additional power when the propulsion output demand is the highest, so that the engine operates as close as possible to the highest efficiency. In the present invention, one hydraulic pump / motor and accumulator perform both functions. To apply additional load to the engine, the engine operates at the power level corresponding to the highest efficiency, and the excess power is delivered into the accumulator through a hydraulic (pumped) pump / motor, and the excess output is very slight energy loss. Is stored as. To deliver additional power, the stored energy is released to the powertrain through a hydraulic pump / motor (motorized).

In a simple configuration, when power is not needed from the power train, the clutch arrangement between the transmission and the wheels allows freewheel operation. For simplicity, no clutch configuration is provided between the engine, hydraulic pump / motor and transmission. Thus, during the regenerative braking action, a drag is formed in the powertrain, in which the pump / motor fills the accumulator or is somewhat reduced by the pump / motor. Due to the small displacement of the engine and a short time in the operating mode, frictional losses associated with the arrangement are minimized.

The present invention includes two or more configurations for the hydraulic regenerative braking function. In the first embodiment, the friction brake is activated and then hydraulic braking is started. According to this method, the control sensitivity required for smooth transmission of power from the wheels is reduced, and safety in the event of hydraulic system failure is ensured. In the second embodiment, hydraulic braking is first formed by the friction brake added as a back up system. The second embodiment is more complicated to control, but is preferred because it recovers maximum braking energy.

When accelerating from a stationary state, the engine provides output to the wheels through the non-hydraulic portion of the drive line. When more power is needed than the engine can provide, additional power is provided by a motor / pump. The accumulator has a sufficient size to provide additional power two or three times in succession. An accumulator capacity for one or more accelerations is required for regenerative braking, and a capacity for another acceleration is required if regenerative braking cannot be provided at standstill.

When the running speed is reached and the power demand falls to a low level, the engine output matches the road load because the engine is small enough that the maximum efficiency of the engine matches the load characteristics of the average road load. To achieve maximum operating efficiency, when more power is required of the engine, additional load is provided by filling the accumulator through a pumped / motored pump. If the accumulator cannot be further charged, the displacement of the pump / motor is set to zero and the engine only operates at reduced power. While running, since the size of the engine is provided to approximate the average output load, there is no compensating action in the setting function. In addition, if the load is very small, such as at low speed travel and standstill, the engine can be stopped and the accumulator can drive a motor / function pump / motor.

If a braking action takes place and there is sufficient storage capacity stored in the accumulator and not in use, regenerative braking occurs and the pump / motor acts as a pump / motor to pressurize the accumulator. If no storage capacity remains inside the accumulator, friction brakes are used. The system is configured such that there is sufficient storage capacity available for normal braking.

If acceleration is required suddenly while driving, the engine power is increased along the best efficiency curve to accelerate the vehicle. When the engine output is reached with maximum efficiency, the hydraulic auxiliary system is activated to recover additional power from the accumulator through the pump / motor.

As in traffic jams, when the vehicle runs at very low speeds, the engine is stopped and a pump / motor and accumulator are used to drive the vehicle. Since the pump / motor can operate with good efficiency even at low speeds and low power requirements, the configuration is much more advantageous than using an engine only in this mode.

Through proper selection of component sizes and optimization of the control system, the system can be designed to optimize several purposes. For example, it minimizes the possibility of (a) colliding with a fully charged accumulator when renewable braking energy is available, or (b) depleting the accumulator by several rapid accelerations without recharging the accumulator. can do.

Using small engines assisted by accumulators with limited energy storage capacity is difficult when accelerating long slopes. Like the acceleration action, the upward slope requires a considerable amount of power and, unlike the acceleration action, the long slope requires the power for an extended time. Since the operation principle of the present invention is to provide a considerable amount of power related to the acceleration action by the hydraulic accumulator, the long inclined surface depletes the accumulator for a short time, and the power of the vehicle becomes insufficient.

Optionally for extremely large accumulator capacities, a second engine, which is only suitable for durability and inexpensive, is clutched, since it is temporarily used to assist the first engine and pump / motor for unlimited time,

An embodiment suitable for a vehicle having a weight of 3,000 to 4,000 pounds is shown in FIG. 1. Energy is transferred to the system by the engine 1 of the small internal combustion engine (for example having 20 hp). Energy is transferred along the drive shaft 2 forming the first drive train, in this embodiment a transmission 3 such as continuously variable transmission CVT or a pump / motor 7 (operating as a pump in the second mode). May be delivered to the transmission 3 and to the pump / motor 7. The pump / motor 7 is a reversible hydraulic displacement generator, such as a swashplate pump, in which a flow reversal function is provided to the pump or to a curved shaft pump within the pump / motor 7, the valve outside the pump When the action is taken, the flow reversal function can operate as a motor in the first mode or as a pump in the second mode. The pump / motor 7 has various displacements. The fluid is pumped to the accumulator 6 and the fluid B is compressed against the gas A by the energy delivered to the pump / motor 7 (acting as a pump). Energy transmitted to the transmission 3 is transmitted along the drive shaft 9 via the freewheel clutch 4 to the wheels 5. The pump / motor 7 is converted into a first mode and a second mode, and the displacement of the pump / motor 7 is changed by the mode controller 20 in response to the signals FPs.

When the power required at the wheels 5 is only greater than the output deliverable by the engine 1, additional power is supplied by the pump / motor 7 (which acts as a motor in the first mode). In the first mode, the pressurized fluid inside the accumulator 6 enters the pump / motor 7 (acting as a motor) and flows along the drive shaft 30 to the drive shaft 2 and the transmission 3. And forms a mechanical output that is transmitted to the wheel 5. The hydraulic accumulator 6, the pump / motor 7 and the drive shaft 30 constitute a second drive train forming a "parallel structure" with the first drive train.

An engine control device 26, such as a fuel injection pump, controls the fuel injection amount for the engine 1 in response to the signal Es and the signal Es is a function of engine speed. The signal Es is a signal produced by the microprocessor 18 or directly input from the speed sensor 40.

The vehicle speed sensor 12, such as the rpm sensor for detecting the rotational speed of the drive shaft configured in the downstream position of the freewheel clutch 4, detects the pressure inside the accumulator 6 and generates a signal Ps indicating the detected pressure. An output request sensor 14, such as a pressure sensor 16 and a sensor for sensing the position of the "accelerator", is included in the control hardware for vehicle operation. A signal Ps sensed by the pressure sensor 16 and indicative of the fluid pressure is input to the first processor 42, and the sensed fluid pressure by the first processor 42 is compared with a predetermined minimum fluid pressure. When the sensed fluid pressure is less than the predetermined minimum fluid pressure, the signal FPs is generated by the first processor 42. The signal FPs is transmitted to the mode controller 20 so that the pump / motor 7 switches to a second mode for operating as a pump and stores energy in the form of fluid pressure inside the accumulator 6.

The additional power along the signal FPs is determined by the second processor 44, and the engine output is generated as the sum of the required power detected by the output demand sensor 14 and the additional power. The transmission signal Ts indicating the optimum engine speed is transmitted to the engine speed controller 24 by the determined vehicle speed. In response to the signal Ts, the engine speed is controlled by the engine speed controller 24 by changing the effective diameter of the pulley 22 configured in the transmission 3 such as a continuously variable transmission. The processors 42, 44, 46 may optionally be comprised of one microprocessor 18 including a memory 48. The signal Ts is determined by referring to two dimensional maps stored in the memory 48 where the values for the optimum efficiency output and engine speed are compared. When the vehicle speed and the required engine speed detected from the vehicle speed sensor 12 are calculated, the signal Ts is calculated. Likewise, the control device can be applied to the following other embodiments.

An additional reserve may be provided by the optional second engine 10. In this case, the electronically controlled clutch 11 is connected, and the output of the engine 10 is supplied to the inside of the apparatus including the engine 1 by the clutch 11. The second engine 10 provides auxiliary outputs for accelerated driving in harsh or repeated acceleration and long and steep slopes. The second engine 10 and the clutch 11 are configured as in the drawing (to transmit the output to the drive shaft 2) or directly transmit the output to the drive shaft 9. The engine 10 is electronically started and the clutch 11 is connected in response to a signal SEs generated, for example, as a function of the sensed "accelerator" position and the fluid pressure inside the accumulator. The second engine 10 is connected at the output speed of the first engine 1 by the clutch 11. The combination of the first engine 1 and the second engine 10 may be considered functionally equivalent to engines of various displacements.

When the power required at the wheels 5 is zero, in response to the signal Cs of the microprocessor 18 and detaching the freewheel clutch 4, the vehicle is switched to the coasting mode. By this method, the vehicle is isolated from rotational friction losses in the drivetrain, so that all of the kinetic energy of the vehicle is used to overcome rolling resistance and aerodynamic drag. Normally the freewheel clutch 4 is disconnected only when it is connected and the required output detected by the output request sensor 14 is zero.

When the vehicle is braked, a regenerative braking function is formed. Kinetic energy is transmitted from the wheels 5 via the freewheel clutch 4 and the transmission 3 to the pump / motor 7 (acting as a pump) along the drive shaft 2. As described above, the pump / motor 7 pressurizes the fluid and stores energy in the accumulator 6.

In order to start the engine 1, the pump / motor 7 operating as a motor in the first mode uses the fluid pressure in the accumulator 6, and as a result, the starting motor of the prior art is unnecessary.

The operation of the present invention is described more clearly with reference to FIGS. 2A-2E. According to the following description, "optimum efficiency" is a range of speeds and loads between points A and B, and the efficiency of the engine 1 is considered to be reasonably close to optimum efficiency.

Referring to FIG. 2A, it is a graph showing the case where an output larger than the output that can be delivered at optimum efficiency by the engine 1 configured in the embodiment of FIG. 1 (at point B) is required. In this case, the load of the portion exceeding the point B is provided by the pump / motor 7 (which acts as a motor), and the load of the remaining portion is provided by the engine 1. In embodiments in which the shafts of the engine and pump / motor are not clutched or geared, the input shafts of engine 1, pump / motor 7 and transmission 3 operate at the same speed. A clutch or gear reduction arrangement can be provided without changing the basic function of the mode.

Referring to FIG. 2B, the system operation of FIG. 1 is shown in mode 2 where the power required for engine 1 falls within the range of optimum efficiency (between point A and point B). The required output for the engine 1 is determined by the microprocessor 18, which takes into account the output required by the output demand sensor 14 and allows the inflow and outflow of the output to the accumulator 6. Decide If power supply from the accumulator 6 is not necessary, all power is supplied by the engine 1, and the stroke of the pump / motor 7 is zeroed (ie neutral position) by the mode controller 20, and The pump / motor 7 does not pressurize fluid into the accumulator 6 or power the apparatus.

Referring to FIG. 2C, the driver's required output is satisfied by the engine 1, and it is necessary to pressurize the accumulator 6 (ie, the energy level of the accumulator reaches a predetermined minimum level and the engine 1 is optimal). There is a request to pressurize the accumulator 6 (ie, the engine 1 needs to operate at optimum efficiency at the driver's required output level point a) (mode 3). . In Fig. 2C, when the required road surface load is shown as one of points (a) or (b), the output of the engine increases to point (c) where sufficient transient power is generated along the optimum efficiency line. Transient outputs that are not used for road loads are supplied to the pump / motor 7 (acting as a pump), and the pump / motor 7 stores the transient output in the accumulator for the next mode 1 or mode 4. .

2D shows Mode 4 in which road surface loads are small. In this case, it is not possible to deliver a significantly small output at an acceptable efficiency by the engine, and considerable pressure is present in the side pressure regulator 6. The fuel inlet to the engine is shut off and the pump / motor 7 (acting as a motor) provides its own output.

Regenerative braking can be considered an extension of mode 4 (FIG. 2D), where the required power is zero in mode 4, and the vehicle must be decelerated at a rate greater than the rate of deceleration generated by rolling resistance and aerodynamic drag. do. The driver actuates the brake, which in turn activates the pump / motor (which acts as a pump), which is the movement of the vehicle obtained through the drive shaft 2, the transmission 3 and the drive shaft 9 Pressurize the fluid using energy. As a result, deceleration similar to the deceleration by the friction braking function is achieved, and energy is stored in the accumulator 6 without waste.

Another embodiment suitable for operation involving a wider range of stop and drive functions is shown in FIG. 3. When the stop and drive operations continue, the pump / motor is switched to the mode in which the vehicle is directly driven without the engine being operated. A clutch 8 is configured between the engine 1 and the pump / motor 7, which disconnects the connection with the engine 1 in this mode and prevents frictional action associated with the operation of the engine 1.

In another embodiment shown in FIG. 4, a second pump / motor 13 is configured between the wheels 5 and the transmission 3. According to the configuration of FIG. 4, the regenerative braking energy is transmitted directly to the accumulator 6 through the second pump / motor 13 without generating friction loss while passing through the transmission 3. If in the neutral position the drag of the second pump / motor 13 is sufficiently small, the second pump / motor 13 may be directly geared to the drive shaft 9 in all driving modes. To remove the drag in the "neutral" state, a clutch can be added between the second pump / motor 13 and the drive shaft 9. In the acceleration and drive mode, the size of the first pump / motor 7 can be reduced because the second pump / motor 13 can power the wheels. As the size of the pump / motor 7 decreases, the size of the pump / motor 7 can be selectively operated to better match the size of the selected motor with respect to the power required by the wheels, so that the average The efficiency can be improved. This effect is very important when frequenting downtown with small or moderate acceleration, and the pump / motor 7 of relatively small size can assist the first engine 1 more efficiently for small power increments. With the addition of a second pump / motor 13, which is used for high acceleration and steep ramps, the size of the transmission can be significantly reduced, so that the second pump / motor is very important in a continuously variable transmission. For steep slopes, the engine 10 may operate and the pump / motor 7 may operate as a pump that drives the pump / motor 13 as a motor. Optionally, a pump is attached to the engine 10 to remove the clutch 11 and supply power through the pump / motor 13 with motor function.

In a further embodiment of FIG. 5, as in the embodiment of FIGS. 1, 3, and 4, the drive shaft 9 is located at an upstream or downstream position of the freewheel clutch 4 rather than the rear position of the first engine 1. The second engine 10 is directly clutched. With this configuration, energy generated in the second engine 10 is transferred directly to the wheels 5 without causing a loss between the elements located at the top of the drive system, and the size of the transmission 3 is reduced. In all positions, the second engine 10 is configured to provide additional power as well as to provide additional power while driving on a steep slope, as well as to provide acceleration while a very strong acceleration action is required. Better engine size selected for power and road load requirements for various purposes to provide emergency power for start-up and to provide auxiliary power during normal acceleration to reduce the size of the accumulator or pump / motor. Optional power is provided to ensure a consistent match.

According to the modification of the embodiment shown in FIG. 3, the transmission 3 is removed and the vehicle is started by the pump / motor 7 by using the freewheel clutch 4 suitably.

According to a modification of the embodiment shown in FIG. 4, it is possible to remove the (optionally clutch and) transmission 3 and add a clutch between the pump / motor 13 and the drive shaft 9. The vehicle is started by the pump / motor 7 or the pump / motor 13 (which supports the clutch 8). At speeds above a certain minimum speed (eg, 20 miles per hour), the engine 1 is connected to provide direct axial force and operate as described above. This configuration eliminates the risk of exhaustion of the pressure in the accumulator.

The control logic flow by the microprocessor 18 is shown in FIG. 6. According to the flowchart of FIG. 6, the control flow is processed by the computer unit or the microprocessor 18. In step S1, a determination is made by a signal transmitted from the brake sensor 50 as to whether the brake is connected. When the brake is connected (Y), the connection of the engine 1 is disconnected to allow regenerative braking action by the pump / motor of the pump function to convert the braking energy to the fluid pressure stored in the accumulator 6. . In step S2, a determination is made as to whether the braking action is required in addition to the regenerative braking function. If necessary, friction brakes are engaged. In step S3, whether the output is required or not is determined according to the signal transmitted from the output request sensor 14. If no output is required, the accumulator pressure, which is determined as a function of the signal transmitted from the pressure sensor 16, is compared with the lowest value of the accumulator pressure, and if less than the minimum value, the engine outputs the engine output in the form of hydraulic energy. The pump / motor (7) with the pump function continues to operate so as to convert to. If it is determined that the oil pressure sensed by the pressure comparing function of step S4 is larger than the minimum value, the engine is stopped and the control cycle is started again. If it is determined in step S3 that the output is required by the driver, then the control action proceeds to step S5, where in step S5 the engine is determined to operate at optimum efficiency for the required output and the vehicle speed. Determination is made by referring to the curve concerning the optimum efficiency with respect to the relationship between the vehicle speed stored in the memory 48 (all points on the curve indicate the intrinsic power level) and the engine output torque (ie load). If it is determined in step S5 that the engine 1 is operating within the range of optimum efficiency, the control action proceeds to step S6 to determine whether the sensed fluid pressure is equal to or greater than the specified maximum value of the fluid pressure. do. If the fluid pressure is greater than the maximum value determined in step S6, the output required by the driver is supplied by the operation of the pump / motor 7 of the motor function operated by the fluid pressure of the accumulator 6. When the fluid pressure of the accumulator is not the predetermined maximum value, the control action proceeds to step S7, in which the sensed fluid pressure is compared with the lowest value of the fluid pressure and the sensed fluid pressure is If less than the minimum value, the control action proceeds to step S8, and in step S8, it is determined whether additional engine power is available, and if additional engine power is available, the additionally available engine power is pumped. It is used to further store the fluid pressure in the accumulator by the operation of the functioning pump / motor 7. If it is determined that the fluid pressure sensed in step S7 is not less than the predetermined minimum value or that the engine power is not additionally available in step S8, the control action returns to the control start step. If it is determined in step S5 that the engine 1 is not operating at optimum efficiency, then the control action proceeds to step S9, and in step S9, it is determined whether the engine is operating within the range below the optimum efficiency. do. If it is determined in step S9 that the engine is operating below optimum efficiency, then the control action proceeds to step S10, in which the sensed fluid pressure is compared with the determined lowest value of the fluid pressure and the sensed If the fluid pressure is less than the minimum value, the engine output increases and the pump / motor 7 acts as a pump, increasing the fluid pressure inside the accumulator 6. In step S10, if it is determined that the pressure of the accumulator is not " low pressure ", the power train is driven by a pump / motor 7 of motor function driven by the fluid pressure of the accumulator 6, so that the output demand is Are satisfied.

If in step S9 the engine does not operate below the optimum efficiency range, that is, it is determined that the engine operates above the optimum efficiency range, the control action proceeds to step S11, where the fluid pressure sensed in step S11 is The fluid pressure is compared to a defined "lowest value". If it is determined in step S11 that it is smaller than the "lowest value" of the fluid pressure, the second engine 10 is started (in FIG. 1), the clutch 11 is connected, and both engines 1, 10 are in series. To drive the vehicle. If it is determined in step S11 that the fluid pressure is smaller than the minimum value, the control action proceeds to step S12, and in step S12, it is determined whether additional power is required. If it is determined that additional power is needed, the pump / motor 7 acts as a motor to supply additional power. In step S11, if it is determined that the sensed fluid pressure is greater than the "lowest value" of the fluid pressure, the second engine is not started, but instead the vehicle is the first engine 1 and the pump / motor 7 of the motor function. Driven by

Description of FIG. 6 is as follows.

(1) Set the displacement of the hydraulic pump and the transmission ratio of CVT to the sliding state of the drive wheel so that the required braking level is formed.

(2) Set the transmission ratio of the continuously variable transmission so that the optimum engine speed / power is produced.

(3) Set the transmission ratio of the continuously variable transmission and the displacement of the hydraulic motor so that the output of optimum efficiency is formed.

(4) Set the speed ratio of the continuously variable transmission to form an engine speed for maximum output.

The present invention can be implemented in other forms without departing from the spirit and main characteristics of the present invention. Accordingly, the embodiments of the invention are intended to be illustrative in all respects and non-limiting, and the scope of the invention is set forth by the following claims rather than by the above description, and is within the meaning and range of equivalency of the claims. All variations are allowed.

Claims (16)

Vehicle frame, Wheels rotatably mounted on the vehicle frame, A first engine mounted on the vehicle frame and providing an engine output by a rotational movement of a drive shaft; An output storage means mounted on the vehicle frame, for storing or discharging the output generated by the engine; A first drive train for delivering the engine power to the wheels is configured, a transmission having an adjustable speed input and output is included in the drive train, When driven by the rotational motion of the first engine in the second mode, selectively transmitting the engine output to the output storage means, or when operating as a motor in the first mode, the first drive from the output storage means. Reversible drive means for delivering the output stored in the train The output structure is configured in parallel with the portion of the first drive train, and transmits the output stored in the first mode to the first drive train, and transmits a portion of the engine output to the output storage means and simultaneously A second drive train configured to connect the reversible drive means to the first drive train for transmitting the rotational motion of the engine to the reversible drive means in the second mode, to transfer the remainder to the wheels, Vehicle speed sensor means for detecting the vehicle speed is configured, A storage output sensor means for sensing an output size stored in the output storage means, An output request sensor means for detecting an output required by the driver for the vehicle, A comparison means for comparing the determined minimum value of the stored output with the detected magnitude of the stored output and generating a request signal when it is determined that the detected magnitude is smaller than the predetermined minimum value, Output determination means for determining an additional increment of output in accordance with the request signal, and for determining an engine output as the sum of the detected driver's required output and the additional increment of the output; Engine speed control means is configured to control the rotational speed of the drive shaft in response to a shift signal and change the input speed of the transmission, Engine speed determination means for determining an engine speed of optimum efficiency according to the determined engine output and the detected vehicle speed, and outputting a shift signal indicative of the determined engine speed to the engine speed control means, Engine load control means for controlling the engine output by controlling the fuel supply to the first engine in response to the shift signal, And mode control means for converting the operation of the reversible driving means between the first mode and the second mode in response to the request signal. The method of claim 1, 2nd engine, And a clutch of the second engine for connecting the output of the second engine to the first drivetrain in response to the sensed required output. 3. The apparatus according to claim 2, wherein when the detected maximum requested output is compared with the determined maximum output for the first engine by the comparing means, and the detected requested output exceeds the predetermined maximum output, the comparing means is arranged for the second output. And a command signal for starting the engine and for connecting the clutch of the second engine. 4. The hybrid far west train vehicle according to claim 3, wherein the command signal is generated only when it is determined that the sensed magnitude of the stored output is smaller than the predetermined maximum output. 2. A freewheel clutch according to claim 1, further comprising a freewheel clutch arranged between the transmission and the wheels for separating the wheels from the first drive train in response to a signal indicating that the sensed required output is zero. Hybrid powertrain vehicle. 2. The apparatus of claim 1, further comprising a memory that associates values for engine speed and engine power of the optimum efficiency and includes a stored map, And the determined engine output and the sensed vehicle speed are applied to the map by the engine speed determining means to determine an engine speed of optimum efficiency. A first engine for rotatably driving wheels, reversible driving means, the wheels and the reversible driving means in parallel in parallel, output storage means for storing engine output generated by the first engine, adjustable speed input In the control method of a hybrid powertrain vehicle including a transmission having an engine speed control means for changing the input speed of the transmission, Detect vehicle speed, Detects the output size stored in the output storage means, Detect the power required by the driver for the vehicle, In response to a signal indicative of the requested output greater than the output of the first engine, supplying output from the output storage means to the reversible driving means to use the reversible driving means as a motor to drive the wheels, At the same time (i) the reversible drive means transmits a portion of the output of the first engine into the output storage means in response to the stored output detected as being less than the predetermined value, and (ii) delivers the remaining portion of the output of the first engine. To the wheels, Compares the detected magnitude of the stored output with a predetermined minimum value and generates a request signal if it is determined that the detected magnitude of the stored output is smaller than the predetermined minimum value, Determine the additional power according to the request signal, determine the output of the engine as the sum of the detected required output and the additional output, In response to the shift signal, the input speed of the transmission is changed to control the rotation speed of the first engine, A method for controlling a hybrid power train vehicle, comprising: determining an engine speed having an optimum efficiency according to a determined engine output and a detected vehicle speed, and outputting a shift signal according to the determined engine speed. 8. The apparatus of claim 7, further comprising a memory comprising a first map associated with the values for the optimum engine speed and the determined engine power and a second map correlating the values for the vehicle speed and the transmission signals, Each of the transmission speeds represents the transmission speed (gear) ratio for obtaining the optimum engine speed. The optimum engine speed is determined by selecting an engine speed having an optimum efficiency for the determined engine output and the detected vehicle speed, and applying the determined engine power and the detected vehicle speed to the maps to set the transmission signal. Hybrid power train vehicle control method. Vehicle Frame, Wheels rotatably mounted on the vehicle frame, A first engine mounted on the vehicle frame and configured to provide an engine output by a rotational movement of a drive shaft; A pressure accumulator mounted on the vehicle frame for storing or releasing fluid pressure, A first drive train is configured to transmit the engine output to the wheels, and a continuously variable transmission including one or more pulleys having a variable effective diameter is included in the first drive train. In a first mode, it operates as a motor fluidly driven by the fluid pressure released from the accumulator to provide a motor output to the first drive train, and in a second mode, the first to store the fluid pressure. Reversible fluid displacement means for operating as a pump driven by the rotational movement of the first engine via a drive train is configured, Coupling the reversible fluid displacement means to the first drive train, in the first mode, transmitting the motor output to the first drive train, and in the second mode, transmitting the engine output to the reversible fluid displacement means. A second drive train is configured to Vehicle speed sensor means for detecting the vehicle speed is configured, A pressure sensor is configured to detect the fluid pressure inside the accumulator, An output request sensor means for detecting an output required by the driver for the vehicle, Comparison means for comparing the determined minimum fluid pressure with the sensed fluid pressure and for generating a request signal when it is determined that the sensed fluid pressure is smaller than the determined minimum fluid pressure, Output determination means for determining an additional increment of output in accordance with the request signal, and for determining an engine output as the sum of the detected driver's required output and the additional increment of the output; Engine speed control means is configured to control the rotational speed of the drive shaft in response to a shift signal and change the effective diameter of the pulley, Engine speed determination means for determining an engine speed of optimum efficiency according to the determined engine output and the detected vehicle speed, and outputting a shift signal indicative of the determined engine speed to the engine speed control means, Engine load control means for controlling the engine output by controlling the fuel supply to the first engine in response to the shift signal, Mode control means for converting the operation of the reversible fluid displacement means in response to the request signal between the first mode and the second mode and for changing the displacement of the reversible fluid displacement means in response to the sensed fluid pressure. A hybrid power train vehicle characterized by the above-mentioned. The method of claim 9, 2nd engine, And a clutch of the second engine for connecting the output of the second engine to the first drivetrain in response to the sensed required output. 11. The apparatus according to claim 10, wherein the comparing means determines the second output when the maximum output determined for the first engine and the sensed requested output are compared by comparing means, and when the sensed requested output exceeds the predetermined maximum output. And a command signal for starting the engine and for connecting the clutch of the second engine. 12. The hybrid powertrain vehicle according to claim 11, wherein the command signal is generated only when it is determined that the sensed fluid pressure is less than the predetermined fluid pressure. 10. The apparatus of claim 9, further comprising a freewheel clutch arranged between the transmission and the wheels for separating the wheels from the first drive train in response to a signal indicating that the sensed demand output is zero. Hybrid powertrain vehicle. 10. The apparatus of claim 9, further comprising a memory that relates the figures for engine speed and engine power of the optimum efficiency and includes a stored map, And the determined engine output and the sensed vehicle speed are applied to the map by the engine speed determining means to determine an engine speed of optimum efficiency. Wheels, a first engine for driving the wheels, reversible fluid displacement means, an accumulator for accumulating fluid pressure, a continuously variable transmission having a variable effective diameter and a pulley movable and a mechanical pulley for changing the effective diameter. In a control method of a hybrid powertrain vehicle including a controller for moving to Detect vehicle speed, Detects the fluid pressure inside the accumulator, Detect the power required by the driver for the vehicle, In response to a signal indicative of the required output greater than the output of the first engine, supplying fluid pressure from the accumulator to the reversible fluid displacement means to use the reversible fluid displacement means as a motor to drive the wheels, In response to the detected fluid pressure being less than the predetermined value, pressurizing the fluid pressure into the accumulator using a portion of the output of the first engine to drive the reversible fluid displacement means as a pump, Compares the sensed fluid pressure with the set minimum fluid pressure, and if it is determined that the sensed fluid pressure is less than the set fluid pressure, generates a request signal, Determine additional output according to the request signal, determine the output of the engine as the sum of the detected requested output and the additional output, In response to the shift signal, the effective diameter of the movable pulley is changed to determine the rotational speed of the first engine, A method for controlling a hybrid power train vehicle, comprising: determining an engine speed having an optimum efficiency according to a determined engine output and a sensed vehicle speed, and outputting a shift signal according to the determined engine speed. 16. The apparatus of claim 15, comprising a memory comprising a first map associated with values for optimal engine speed and determined engine power and stored and a second map relating values for vehicle speed and the transmission signals, Each of the transmission speeds represents the transmission speed (gear) ratio for obtaining the optimum engine speed. The optimum engine speed is determined by selecting an engine speed having an optimum efficiency for the determined engine output and the detected vehicle speed, and applying the determined engine power and the detected vehicle speed to the maps to set the transmission signal. Hybrid powertrain vehicle control method.